Field of the Invention
The present invention relates to a vibration reduction apparatus, a lithography apparatus, and a method of manufacturing an article.
Description of the Related Art
In a lithography apparatus for forming a pattern on a substrate, the vibration transferred from the base to the main body of the lithography apparatus is a cause of deterioration in overlay accuracy and transfer accuracy. For this reason, the lithography apparatus uses a vibration reduction apparatus for reducing the vibration of a target object (first object) such as a surface plate on which the main body of the lithography apparatus is mounted.
Japanese Patent Laid-Open No. 2012-97786 and Japanese Patent No. 4083708 have proposed a vibration reduction apparatus which reduces the vibration of a target object supported on the base by using an elastic member (for example, an air spring). The vibration reduction apparatus disclosed in Japanese Patent Laid-Open No. 2012-97786 and Japanese Patent No. 4083708 includes a reference system having a reference object (second object) and an actuator which drives an object. It is possible to reduce the vibration of a target object by performing feedback control so as to make the relative distance between the reference object of the reference system and the target object approach a target distance.
In the vibration reduction apparatus disclosed in Japanese Patent Laid-Open No. 2012-97786 and Japanese Patent No. 4083708, the reference object sometimes vibrates in a predetermined frequency band due to the influence of a disturbance such as an airflow in a place where the reference system is placed. The present inventor has found that in such a situation, performing feedback control on the vibration of a target object with reference to the reference object can vibrate the target object following the vibration of the reference object.